Is it normal to experience a few pimples after applying Tretinoin cream?

Hi doctor,

I was put on a low-dose course of Accutane, and I took it for about 13 months (20 mg). My dermatologist was always going to prescribe cream Tretinoin after the course to help address my scarring or pigmentation. My question is that she prescribed the cream to be used after I have zero spots after a whole box of pills. However, I had almost finished the box with no spots on my skin and decided to stop taking the medication. I waited a month and now am taking the Retin A cream. However, I am experiencing little spots (after around three weeks of every other day application). Is this normal, and would I experience some purging? Or did I make a mistake? But then, would this purging have happened anyway by finishing the rest of the pills? Kindly help. Thank you.